Obesity is defined as a body mass index of greater than 30, whereas overweight is defined as having a body mass index of greater than 25. Approximately 19% of Americans are obese, and 35% are overweight. The incidence of being overweight and obese has increased dramatically in the last decade. In the United States, over $33 billion are spent each year for weight loss products ($0.5 billion alone on drugs) with 14% of adults using prescription drugs for weight loss and 7% using over the counter drugs.
Obesity involves multiple factors that contribute to the disease, including genetic, metabolic, psychosocial, lifestyle, nutrition, exercise, and environmental factors. The great majority of obesity cases are probably due to a complex relationship between the many factors which regulate energy intake and utilization. Obesity is a life-long disorder with adverse health consequences. Obesity is considered the second leading cause of death in the United States and contributes to at least 300,000 deaths per year. It is associated with a number of diseases, including diabetes (80% of type II diabetics are obese), hypertension, gallstones, respiratory problems, and mortality rates for certain types of cancers.
Given the large obese population and the associated problems, the area of obesity research and product development for the management of obesity has been extensively explored, yet the problem remains. The currently available weight management programs almost all take a lifetime commitment by the patients and involve painful lifestyle changes.
Many known pharmaceutical agents designed for weight loss and fat loss have notable side effects. For example, the side effects of adrenergic agents include insomnia, nervousness, irritability, headache, nausea, and constipation. Some adrenergic agents can even increase blood pressure and precipitate angina. The side effects of lipase inhibitors include nausea, vomiting, abdominal pain, oily spotting, fatty oily stool, flatus, fecal urgency, increased defecation, and fecal incontinence. The gastrointestinal side effects could be worse if dietary fat is not reduced. Sibutramine can cause headache, insomnia, constipation, and dry mouth, as well as an increase in blood pressure and pulse rate. Agents that increase energy expenditure such as ephedrine, theophylline, and thyroid hormone carry the risk of cardiac complications from hypertension and increased heart rate. Cholecystokinin is a peptide that activates gastric vagal fibers, and triggers satiety. However, it must be administered parenterally, dramatically limiting its use. Serotonergic agents have been withdrawn from the market after valvular heart disease was reported in patients using the combination of fenfluramine and phentermine.